In an analytical apparatus performing automatically stages from mounting a specimen to a completion of analysis, there are cases wherein a container containing therein the specimen is transferred on the apparatus. For examples of the cases, there are the transfer to next one of the stages, stirring, centrifugal action, temperature control, measuring and so forth. In such analytical apparatus, the container is generally plugged to prevent a content from being discharged from the container during the transfer of the container. Particularly, in an analyzing technique wherein a contamination between the specimens is deemed as a problem, the containers need to be plugged hermetically.
For example, in an analytical apparatus performing a nucleic-acid amplification method such as typically PCR method wherein a nucleic-acid included by the specimen is amplified with a specific base sequence to detect the nucleic-acid of trace amount with high sensitivity, the contamination between the specimens is a significant problem, whereby the hermetical plugging of the containers is of necessary process. An nucleic-acid analyzing device with function of plugging containers on the apparatus is disclosed by, for example, JPA-2003-75303.